Waveguide circulators are known in the art for handling RF waves. Typically, waveguide circulators include three ports (although more or less ports are possible) and are used for transferring wave energy in a non-reciprocal manner, such that when wave energy is fed into one port, it is essentially transferred to the next port only. A common use for waveguide circulators is to transmit energy from a transmitter to an antenna during transmitting operations, and to transmit energy from an antenna to a receiver during receiving operations. In order to enable the non-reciprocal energy transfer, the waveguide circulators include ferrite elements to which are applied a magnetic field via one or more magnets or electromagnets.
An example of a typical waveguide circulator 1 is illustrated in FIGS. 1A and 1B. In this example, the waveguide circulator 1 has three waveguide arms 2, 4 and 6 that meet at a common junction 8. Shown in FIG. 1B is a side view of the waveguide circulator 1 with a view into waveguide arm 6. Positioned within the junction 8 of the waveguide circulator 1 is a pair of gyromagnetic members 5 and 7, which are also referred to as “ferrite elements” and are typically made of a ferrite material. The ferrite elements 5 and 7 are positioned within the junction 8, generally upon mounting posts 50 and 70 located on opposing inner surfaces 3 and 3′ of the junction 8, such that they are centrally disposed and arranged symmetrically, with respect to the three waveguide arms 12, 14 and 16.
During operation, the ferrite elements 5 and 7 are subjected to the influence of a magnetic field that is generated by one or more magnets or electromagnets (not shown), which can be positioned on outside surfaces of the junction 8 above and below the ferrite elements 5 and 7. The magnetic field that is generated is a unidirectional magnetic field, represented by arrow 9 in FIGS. 1A and 1B, such that wave energy entering each waveguide arm 2, 4 and 6 will move in a counter-clockwise direction (or clockwise depending on the direction of the magnetic field) towards its neighboring waveguide arm. As such, the waveguide circulator 1 is a non-reciprocal transmitter of electromagnetic wave energy propagating in the waveguide arms.
A deficiency associated with many waveguide circulators of the type depicted in FIGS. 1A and 1B is that they are bulky, especially once the magnets used to magnetize the ferrite elements are positioned on the outer surfaces of the waveguide circulators.
Another deficiency associated with some waveguide circulators of the type depicted in FIGS. 1A and 1B is that they may require complex handling during manufacturing, which increases the cost of manufacturing such devices. For example, to use a circulator of the type depicted in FIGS. 1A and 1B as a switch, a current carrying wire is often placed inside the ferrites of the circulator, which significantly complicates the design and assembly of the switch.
In light of the above, there is a need in the industry for providing an improved waveguide circulator that alleviates, at least in part, the deficiencies with existing waveguide circulators.